System and method for boosting torque output of a drive train

Abstract

An engine speed detector detects an engine speed of an engine having a baseline torque versus engine speed curve. A torque sensor detects an engine torque of the engine. A data processor determines if the detected engine speed is within a first speed range and if the detected engine torque is within a first torque range. A motor controller activates an electric motor to rotate substantially synchronously with a corresponding engine speed associated with the detected engine torque in an electric propulsion mode in accordance with a supplemental torque versus engine speed curve if the detected engine speed is within the first speed range and if the detected engine torque is within the first torque range. The supplemental torque versus engine speed curve intercepts the baseline torque versus engine speed curve at a lower speed point and a higher speed point.

1. A system for boosting a torque output of a drive train, the system comprising:
 an engine speed detector for detecting an engine speed of an engine having a baseline torque versus engine speed curve; 
 a torque sensor for detecting an engine torque of the engine; 
 a data processor for determining if the detected engine speed is within a first speed range and if the detected engine torque is within a first torque range; and 
 a motor controller for activating an electric motor to rotate substantially synchronously with a corresponding engine speed associated with the detected engine torque within the first range in an electric propulsion mode in accordance with a supplemental torque versus engine speed curve if the detected engine speed is within the first speed range if the detected engine torque is within the first torque range, the supplemental torque versus engine speed curve intercepting the baseline torque versus engine speed curve at a lower speed point and a higher speed point. 
 
   
   
     2. The system according to  claim 1  wherein the motor controller and the data processor are arranged to permit a transition between the baseline torque versus engine speed curve and the supplemental torque versus engine speed curve only at the first lower speed point and the first higher speed point. 
   
   
     3. The system according to  claim 1  wherein the supplemental torque versus engine speed curve is generally parabolic and has an enhanced peak torque between the lower speed point and the higher speed point. 
   
   
     4. The system according to  claim 1  wherein the enhanced peak torque exceeds the baseline torque at any engine speed. 
   
   
     5. The system according to  claim 1  further comprising:
 a status detector for determining if a state of charge of an energy storage device indicates that the energy storage device requires recharging; and 
 the motor controller arranged to deactivate the electric motor for a time period if the stage of charge indicates that the energy storage device requires recharging. 
 
   
   
     6. The system according to  claim 1  further comprising:
 the data processor arranged to determine if a state of charge of an energy storage device indicates that the energy storage device requires recharging; and 
 the motor controller configured to place the electric motor in a power generation mode for a time period, rather than the electric propulsion mode. 
 
   
   
     7. The system according to  claim 1  further comprising:
 the data processor arranged to determine if the detected engine speed is within a second speed range and if the detected torque is within the second torque range; and 
 the motor controller configured to activate an electric motor to rotate substantially synchronously with the engine speed within the second range in an electric propulsion mode in accordance with a second supplemental torque versus engine speed curve if the detected engine speed is within the second speed range and if the detected torque is within the second torque range, the second supplemental torque versus engine speed curve intercepting the baseline torque versus engine speed curve at a second lower speed point and a second higher speed point. 
 
   
   
     8. The system according to  claim 7  wherein the motor controller and the data processor are arranged to permit a transition between the baseline torque versus engine speed curve and the supplemental torque versus engine speed curve only at the second lower speed point and the second higher speed point. 
   
   
     9. The system according to  claim 1  wherein the torque sensor is configured to detect the engine torque during deactivating of the electric motor. 
   
   
     10. The system according to  claim 1  wherein the torque sensor is configured to detect the engine torque while the electric motor is in an active state and, wherein the data processor is programmed to deduct a torque contribution of the electric motor from an aggregate torque based on the baseline torque versus engine speed curve and the supplemental torque versus engine speed curve at an applicable operating point.